US 2005/205154 relates to a closure system for fluid dispensers. The disclosed system is a motorized, articulated system that, in a closed position, provides a cover or closure for a nozzle or nozzle manifold through which one or more fluids are dispensed. In the closed position, the closure element is disposed beneath the nozzle or nozzle manifold and collects any fluid drippings between dispensing operations and also preferably provides a sealing effect. To move the closure system to an open or to a dispense position, a motor is activated which moves the closure element downward before pivoting the closure element away from the nozzle or nozzle manifold.
US 2007/0012378 discloses an apparatus for dispensing a plurality of fluids according to one of a plurality of formulas stored in a controller. The controller is linked to a coordinating board which, in turn, is linked in series to a plurality of pump modules and a manifold module. Each pump module includes its own module board which controls the operation of two pumps associated with that module. The modules, which include the module board, two pumps and two reservoirs as well as motors for driving the pumps, are all mounted on a module frame which is detachably connected to the system so that the modules may be easily changed or replaced. Further, the manifold module may also be easily replaced. The manifold module also includes a motorized closure system.
As explained in US 2007/0012378, in multiple fluid dispensing applications, both precision and speed are important. Precision is important as many formulations require the addition of precise amounts of ingredients. This is true in e.g. the paint, cosmetic, food, chemical, and pharmaceutical industries as the addition of more or less of a key ingredient can result in a noticeable change in the color or product or the efficacy of a product. Speed is important as many products are prepared at a point-of-sale for a customer. For example, paint formulations, cosmetic formulations, hair dyes and various nutritional products are often being prepared in retail environments while the consumer waits.
Further, one way in which the precision of dispensing systems is compromised is “dripping”. Specifically, a “leftover” drip may be hanging from a nozzle that was intended to be added to a previous formulation and, with a new container in place under the nozzle, the drop of liquid intended for a previous formulation may be erroneously added to a new formulation. Thus, the previous container may not receive the desired amount of the liquid ingredient and the next container may receive too much.
To solve the drip problem, various scraper and wiper designs have been proposed. However, these designs often require one or more different motors to operate the wiper element and are limited to use on dispensing systems where the nozzles are separated or not bundled together in a manifold. Use of a wiper or scraping function would not be practical in a multiple nozzle manifold design as the ingredients from the different nozzles will be mixed by the wiper or scraper which would then also contribute to the lack of precision of subsequently produced formulations.
Another problem associated with dispensing systems that make use of nozzles lies in the dispensing of relatively viscous liquids such as tints, colorants, base materials for cosmetic products, certain pharmaceutical ingredients or other fluid materials having relatively high viscosities. Specifically, the viscous fluids have a tendency to dry and cake onto the end of the nozzles, thereby requiring frequent cleaning in order for the nozzles to operate effectively. While some mechanical wiping or scrapping devices are available, these devices are not practical for multiple nozzle manifold systems and the scraper or wiper element must be manually cleaned anyway.
It is an object of the present invention to provide a reliable valve assembly for dispensing a plurality of flowable materials, which can be opened and closed more rapidly e.g. to prevent the materials in the outlets from drying and caking.